TOKYO -- Japanese corporate bankruptcies rose 22.7% in October from a year earlier and debts left behind by insolvent companies surged 1,253.4% to a new post-war high as two mid-sized life-insurance companies failed, private credit-research agency Teikoku Databank Ltd. said Wednesday.

The number of October cases rose 13.9% from September to 1,711 and the amount of debt was up 1,005.8% to 8.561 trillion yen ($80 billion), compared...